How can I prevent my car’s windows from fogging up on the inside?

Turn on both the defrost setting and the AC simultaneously. The AC compressor dehumidifies the air while the defrost directs it onto the windshield, clearing fog in under a minute.

Clean the interior glass thoroughly, then apply a commercial anti-fog product. Dirty glass gives moisture droplets something to cling to, while anti-fog treatments create a hydrophilic surface that prevents fog from forming.

Excess moisture in the cabin is the root cause of interior fogging. Eliminating moisture sources prevents the problem before it starts, reducing dependence on climate controls.